Details of a Researcher - YOKOTA Shinichi

Papers - YOKOTA Shinichi

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入院治療中にアミカシン耐性を獲得した多剤耐性Klebsiella pneumoniaeの全ゲノム解析

佐藤豊孝, 品川雅明, 高橋聡, 横田伸一

日本化学療法学会雑誌 ( (公社)日本化学療法学会 ) 66 ( Suppl.A ) 252 - 252 2018.04

緑膿菌で汚染させた末端透析液および金属腐食ポンプに対する洗浄・消毒効果に関する検討

中村実, 横田伸一, 白石宗, 佐藤豊孝, 木村主幸, 岡山雅哉, 小林陽介, 柴田晴昭, 萩原誠也, 名和伴恭

日本臨床工学技士会会誌 ( (公社)日本臨床工学技士会 ) ( 63 ) 142 - 142 2018.04

Evaluation of consistency in quantification of gene copy number by real-time reverse transcription quantitative polymerase chain reaction and virus titer by plaque-forming assay for human respiratory syncytial virus.

Keisuke Yamamoto, Noriko Ogasawara, Soh Yamamoto, Kenichi Takano, Tsukasa Shiraishi, Toyotaka Sato, Hiroyuki Tsutsumi, Tetsuo Himi, Shin-Ichi Yokota

Microbiology and immunology 62 ( 2 ) 90 - 98 2018.02 [Refereed] [International journal]

The plaque-forming assay is the standard technique for determining viral titer, and a critical measurement for investigating viral replication. However, this assay is highly dependent on experimental technique and conditions. In the case of human respiratory syncytial virus (RSV) in particular, it can be difficult to objectively confirm the accuracy of plaque-forming assay because the plaques made by RSV are often small and unclear. In recent studies, RT-qPCR methods have emerged as a supportive procedure for assessment of viral titer, yielding highly sensitive and reproducible results. In this report, we compare the viral replication, as determined by plaque-forming assay, and the copy numbers of RSV genes NS1, NS2, N, and F, as determined by RT-qPCR. Two real-time PCR systems, SYBR Green and TaqMan probe, gave highly similar results for measurement of copy numbers of RSV N genes of virus subgroups A. We determined the RSV gene copy numbers in the culture cell supernatant and cell lysate measured at various multiplicities of infection. We found that copy number of the RSV N gene in the culture supernatant and cell lysate was highly correlated with plaque-forming units. In conclusion, RT-qPCR measurement of RSV gene copy number was highly dependent on viral titer, and the detailed comparison between each gene copy number and virus titer should be useful and supportive in confirming RSV plaque-forming assay and virus dynamics. The technique may also be used to estimate the amount of RSV present in clinical specimens.

DOI PubMed

β-lactamase-negative ampicillin-resistant Haemophilus influenzae臨床分離株の遺伝学的特徴

本田宏幸, 佐藤豊孝, 高橋弘毅, 横田伸一

日本細菌学雑誌 ( 日本細菌学会 ) 73 ( 1 ) 147 - 147 2018.02

種特異的な構造を有するLactobacillus gasseriリポテイコ酸のヒト腸管上皮細胞株でのIL-8産生への影響

久富亮佑, 白石宗, 佐藤豊孝, 横田伸一

日本細菌学雑誌 ( 日本細菌学会 ) 73 ( 1 ) 89 - 89 2018.02

大腸菌臨床分離株におけるepidemic clone ST131のコリスチンおよびチゲサイクリン耐性(Colistin and tigecycline resistance in an epidemic clone, ST131, Escherichia coli clinical isolates)

佐藤豊孝, 臼井優, 品川雅明, 福田昭, 本田宏幸, 白石宗, 田村豊, 高橋聡, 横田伸一

日本細菌学雑誌 ( 日本細菌学会 ) 73 ( 1 ) 146 - 146 2018.02

High prevalence of mcr-1, mcr-3 and mcr-5 in Escherichia coli derived from diseased pigs in Japan.

Akira Fukuda, Toyotaka Sato, Masaaki Shinagawa, Satoshi Takahashi, Tetsuo Asai, Shin-Ichi Yokota, Masaru Usui, Yutaka Tamura

International journal of antimicrobial agents 51 ( 1 ) 163 - 164 2018.01 [Refereed] [International journal]

DOI PubMed

Lipoteichoic acids are embedded in cell walls during logarithmic phase, but exposed on membrane vesicles in Lactobacillus gasseri JCM 1131T

T. Shiraishi, S. Yokota, Y. Sato, T. Ito, S. Fukiya, S. Yamamoto, T. Sato, A. Yokota

Beneficial Microbes ( Wageningen Academic Publishers ) 9 ( 4 ) 653 - 662 2018 [Refereed]

Lipoteichoic acid (LTA) is a cell surface molecule specific to Gram-positive bacteria. How LTA localises on the cell surface is a fundamental issue in view of recognition and immunomodulation in hosts. In the present study, we examined LTA localisation using strain JCM 1131T of Lactobacillus gasseri, which is a human intestinal lactic acid bacterium, during various growth phases by immunoelectron microscopy. We first evaluated the specificity of anti-LTA monoclonal antibody clone 55 used as a probe. The glycerophosphate backbone comprising almost intact size (20 to 30 repeating units) of LTA was required for binding. The antibody did not bind to other cellular components, including wall-teichoic acid. Immunoelectron microscopy indicated that LTA was embedded in the cell wall during the logarithmic phase, and was therefore not exposed on the cell surface. Similar results were observed for Lactobacillus fermentum ATCC 9338 and Lactobacillus rhamnosus ATCC 7469T. By contrast, membrane vesicles were observed in the logarithmic phase of L. gasseri with LTA exposed on their surface. In the stationary and death phases, LTA was exposed on cell wall-free cell membrane generated by autolysis. The dramatic alternation of localisation in different growth phases and exposure on the surface of membrane vesicles should relate with complicated interaction between bacteria and host.

DOI

Tigecycline susceptibility of Klebsiella pneumoniae complex and Escherichia coli isolates from companion animals: the prevalence of tigecycline-nonsusceptible K. pneumoniae complex, including internationally expanding human pathogenic lineages

Sato T, Harada K, Usui M, Tsuyuki Y, Shiraishi T, Tamura Y, Yokota S

Microbial Drug Resistance 24 ( 6 ) 860 - 867 2018 [Refereed]

Complete Genome Sequence of Multidrug-Resistant Streptococcus pneumoniae Serotype 19F Isolated from an Invasive Infection in Sapporo, Japan.

Toyotaka Sato, Yasuo Ohkoshi, Takayuki Wada, Yukari Fukushima, Hiromi Murabayashi, Yasunari Takakuwa, Kaoru Nishiyama, Tsukasa Shiraishi, Chie Nakajima, Yasuhiko Suzuki, Shin-Ichi Yokota

Genome announcements 5 ( 44 ) e01239-17 2017.11 [Refereed] [International journal]

DOI PubMed

The role of transcriptional factor p63 in regulation of epithelial barrier and ciliogenesis of human nasal epithelial cells

Yakuto Kaneko, Takayuki Kohno, Takuya Kakuki, Ken-ichi Takano, Noriko Ogasawara, Ryo Miyata, Shin Kikuchi, Takumi Konno, Tsuyoshi Ohkuni, Ryoto Yajima, Akito Kakiuchi, Shin-ichi Yokota, Tetsuo Himi, Takashi Kojima

SCIENTIFIC REPORTS ( NATURE PUBLISHING GROUP ) 7 ( 1 ) 10935 2017.09 [Refereed]

Disruption of nasal epithelial tight junctions (TJs) and ciliary dysfunction are found in patients with chronic rhinosinusitis (CRS) and nasal polyps (NPs), along with an increase of p63-positive basal cells and histone deacetylase (HDAC) activity. To investigate these mechanisms, primary cultures of HNECs transfected with human telomerase reverse transcriptase (hTERT-HNECs) were transfected with siRNAs of TAp63 and Delta Np63, treated with the NF-kB inhibitor curucumin and inhibitors of HDACs, and infected with respiratory syncytial virus (RSV). In TERT-HNECs, knockdown of p63 by siRNAs of TAp63 and Delta Np63, induced claudin-1 and -4 with Sp1 activity and enhanced barrier and fence functions. The knockdown of p63 enhanced the number of microvilli with the presence of cilia-like structures. Treatment with curcumin and inhibitors of HDACs, or infection with RSV prevented expression of p63 with an increase of claudin-4 and the number of microvilli. The knockdown or downregulation of p63 inhibited phospho-p38MAPK, and the p38MAPK inhibitor downregulated p63 and upregulated the barrier function. Thus, epithelial barrier and ciliogenesis of nasal epithelium are regulated in a p63-negative manner in normal and upper airway diseases. Understanding of the regulation of p63/p38 MAPK/NF-kappa B may be important in the therapy for airway allergy and its drug delivery system.

DOI

Novel antimicrobial activities of a peptide derived from a Japanese soybean fermented food, Natto, against Streptococcus pneumoniae and Bacillus subtilis group strains

Manabu Kitagawa, Tsukasa Shiraishi, Soh Yamamoto, Ryosuke Kutomi, Yasuo Ohkoshi, Toyotaka Sato, Hideki Wakui, Hideaki Itoh, Atsushi Miyamoto, Shin-ichi Yokota

AMB EXPRESS ( BIOMED CENTRAL LTD ) 7 127 2017.06 [Refereed]

We recently isolated a tumoricidal peptide from Natto, a Japanese traditional fermented food. In the present study, antimicrobial activity of the Natto peptide was examined. The peptide consisted of 45 amino acid residues, and its structure was predicted to be rich in alpha-helix. It excreted antimicrobial activity only against Streptococcus pneumoniae and Bacillus subtilis group (B. subtilis, Bacillus pumilus, and Bacillus licheniformis). Lesser antimicrobial activity was observed for Streptococcus species other than S. pneumoniae. Hemolysate or hemin was required for the antimicrobial activity of the peptide. The Natto peptide damages the cell membrane of B. subtilis. On the other hand, chain morphology was induced in S. pneumoniae, which is naturally diplococcus, during the early phases of the Natto peptide treatment; following that the cells were rapidly lysed. This suggested that the Natto peptide displayed a novel narrow spectrum of bactericidal activity and inhibited cell separation during cell division of S. pneumoniae.

DOI

Mycoplasma bovis isolates from dairy calves in Japan have less susceptibility than a reference strain to all approved macrolides associated with a point mutation (G748A) combined with multiple species-specific nucleotide alterations in 23S rRNA

Toyotaka Sato, Hidetoshi Higuchi, Shin-ichi Yokota, Yutaka Tamura

MICROBIOLOGY AND IMMUNOLOGY ( WILEY ) 61 ( 6 ) 215 - 224 2017.06 [Refereed]

Erythromycin, tylosin and tilmicosin are approved for use in cattle in Japan, the latter two being used to treat Mycoplasma bovis infection. In this study, 58M. bovis isolates obtained from Japanese dairy calves all exhibited reduced susceptibility to these macrolides, this widespread reduced susceptibility being attributable to a few dominant lineages. All 58 isolates contained the G748A variant in both the rrl3 and rrl4 alleles of 23S rRNA, whereas a reference strain (PG45) did not. G748 localizes in the central loop of domain II (from C744 to A753) of 23S rRNA, which participates in binding to mycinose, a sugar residue present in both tylosin and tilmicosin. A number of in vitro-selected mutants derived from M. bovis PG45 showed reduced susceptibility to tylosin and tilmicosin and contained a nucleotide insertion within the central loop of domain II of rrl3 (U747-G748Ins_CU/GU or A743-U744Ins_UA), suggesting that mutations around G748 confer this reduced susceptibility phenotype. However, other Mycoplasma species containing G748A were susceptible to tylosin and tilmicosin. Sequence comparison with Escherichia coli revealed that M. bovis PG45 and isolates harbored five nucleotide alterations (U744C, G745A, U746C, A752C and A753G) in the central loop of domain II of 23S rRNA, whereas other Mycoplasma species lacked at least two of these five nucleotide alterations. It was therefore concluded that G748 mutations in combination with species-specific nucleotide alterations in the central loop of domain II of 23S rRNA are likely sufficient to reduce susceptibility of M. bovis to tylosin and tilmicosin.

DOI

Lactobacillus gasseri種に共通する種特異的なリポテイコ酸の化学構造

久富亮佑, 白石宗, 佐藤耶舞羽, 森田直樹, 吹谷智, 佐藤豊孝, 横田篤, 横田伸一

日本乳酸菌学会誌 ( 日本乳酸菌学会 ) 28 ( 2 ) 123 - 123 2017.06

Involvement of herpes simplex virus type 1 UL13 protein kinase in induction of SOCS genes, the negative regulators of cytokine signaling

Yuka Sato, Tetsuo Koshizuka, Kei Ishibashi, Koichi Hashimoto, Ken Ishioka, Kazufumi Ikuta, Shin-ichi Yokota, Nobuhiro Fujii, Tatsuo Suzutani

MICROBIOLOGY AND IMMUNOLOGY ( WILEY ) 61 ( 5 ) 159 - 167 2017.05 [Refereed]

The suppressor of cytokine signaling (SOCS) family has eight members and suppresses various cytokine signaling pathways, including IFN signaling. Therefore, some viruses have evolved molecular mechanisms for inducing SOCS proteins and thus escaping host immunity. Herpes simplex virus type 1 (HSV-1) has a mechanism for escaping from type I IFN by induction of both SOCS1 and SOCS3. In this study, expression of the eight members of the SOCS family stimulated by HSV-1 infection was comparatively analyzed by qRT-PCR. It was found that SOCS1 and SOCS3 are induced by HSV-1-infection at 4 hr post infection. However, such induction was not observed in UL13 deficient virus-infected cells, suggesting that UL13 protein kinase participates in induction of both genes. The transcription factor Sp1-binding sites of SOCS3 promoter/enhancer region were identified as the regulatory elements for induction of SOCS3 in HSV-1 infected cells. Accumulation of activated Sp1 was detectable in the nuclei of HSV-1-infected cells before induction of SOCS3. Taken together, these results suggest that HSV-1 has a potent mechanism for escaping from the IFN system.

DOI

ヒト鼻粘膜上皮バリアにおける転写制御因子p63の役割

金子躍人, 角木拓也, 高野賢一, 小笠原徳子, 横田伸一, 氷見徹夫, 幸野貴之, 小島隆

日本病理学会会誌 ( (一社)日本病理学会 ) 106 ( 1 ) 321 - 321 2017.03

大腸菌臨床分離株におけるフルオロキノロン系抗菌薬耐性とチゲサイクリン耐性との関連性

佐藤豊孝, 品川雅明, 高橋聡, 横田伸一

日本化学療法学会雑誌 ( (公社)日本化学療法学会 ) 65 ( Suppl.A ) 274 - 274 2017.03

マクロライド作用機序クラリスロマイシンの炎症反応修飾作用の分子機構の解明気道上皮細胞のクラリスロマイシン結合タンパク質の同定と機能解析

横田伸一, 山本聡, 小笠原徳子, 植村知加, 高谷芳明, 伊藤英晃, 山本圭佑, 白石宗, 佐藤豊孝, 氷見徹夫

The Japanese Journal of Antibiotics ( (公財)日本感染症医薬品協会 ) 70 ( Suppl.A ) 60 - 64 2017.03

ウイルス、細菌、真菌クラリスロマイシンは気道上皮細胞でRSウイルスによって誘導されるインターフェロンの産生をIRF-3を介して調整する

山本圭佑, 小笠原徳子, 山本聡, 堤裕幸, 氷見徹夫, 横田伸一

The Japanese Journal of Antibiotics ( (公財)日本感染症医薬品協会 ) 70 ( Suppl.A ) 19 - 24 2017.03

患者の手術で採取した鼻粘膜から作製したhTERT導入鼻粘膜上皮細胞(hTERT-HNEC)、肺胞上皮由来細胞株(A549)、ヒト気道上皮細胞株(BEAS-2B)を用い、ヒト気道上皮細胞における急性呼吸器ウイルス感染症に対するクラリスロマイシン(CAM)の効果と、CAMのもつ免疫調節効果のメカニズムを調べるため各種検討した。RSウイルス(RSV)感染のCAMの影響を調べ、CAMがRSV増殖に影響を与えないことが示唆された。hTERT-HNEC、A549、BEAS-2Bなどの気道上皮細胞においてPoly:C処置、RSV感染で誘導されるIFN-β、IFN-λがCAMにより強く抑制された。宿主の自然免疫に関わる転写因子IRF、NF-κB、AP-1の結合領域を含むプロモーター活性化がCAMにより強く抑制された。

Haemophilus influenzaeのキノロン系抗菌薬耐性獲得機序についての検討

本田宏幸, 佐藤豊孝, 高橋弘毅, 横田伸一

感染症学雑誌 ( (一社)日本感染症学会 ) 91 ( 臨増 ) 376 - 376 2017.03

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Papers - YOKOTA Shinichi